• Proceedings of the Korean Aquaculture Society Conference
• /
• 2006.05a
• /
• pp.381-382
• /
• 2006

• Fisheries and Aquatic Sciences
• /
• v.12 no.4
• /
• pp.265-275
• /
• 2009

G Protein-coupled receptors (GPCRs) mediating wide ranges of physiological responses is one of the most attractive targets for drug development. Rhodopsin, a dim-light photoreceptor, has been extensively used as a model system for structural and functional study of GPCRs. Fish have rhodopsin finely-tuned to their habitats where the intensity and the wavelength of lights are changed depending on its water-depth. To study the detailed molecular characteristics of GPCR architecture and to understand the fishery light-sensing system, genes encoding rod opsins were isolated from fishes living under different photic environments. Full-length rod opsin genes were obtained by combination of PCR amplification and DNA walking strategy of genomic DNA isolated from olive flounder, P. olivaceus, Japanese eel, A. japonica, and Common carp C. carpio. Deduced amino acid sequences showed a typical feature of rod opsins including the sites for Schiffs base formation (Lys296) and its counter ion (Glu113), disulfide formation (Cys110 and Cys187), and palmitoylation (Cys322 and Cys323) although Cys322 is replaced by Phe in Japanese eel. Comparison of opsins by amino acid sequence alignment indicated the closest similarity between P. olivaceus and H. hippoglossus (94%), A. japonica and A. anguilla (98%), and C. carpio and C. auratus (95%), respectively.

• Journal of Life Science
• /
• v.20 no.12
• /
• pp.1743-1749
• /
• 2010

A research group demonstrated that the 37 kDA protein of Edwardsiella tarda, a causing causative agent of edwardsiellosis in fish, exhibited high antigenicity in Japanese flounder. The research group also showed that the N-terminus amino acid sequences of the 37 kDa protein were mapped to the N-terminus of GAPDH (glyceraldehyde-3-phosphate dehydrogenase). Using degenerated primer sets based on the known N-terminus sequence, the corresponding E. tarda DNA was amplified and cloned. The nucleotide sequences of the cloned gene revealed high homology with a bacterial gene for GAPDH, as we was expected. The amino acid sequence of E. tarda GAPDH (etGAPDH) revealed a <70% similarity with GAPDH proteins in other Enterobacteriaceae. With the application of artificial protein overexpression system in Escherichia coli, the recombinant etGAPDH (rGAPDH) was produced and purified. In this study, Using the purified rGAPDH, the etGAPDH specific polyclonal antibody has been was generated using the purified rGAPDHin this study. The immunoblotting analyses demonstrated that the location of the GAPDH protein is located with the association of is associated with the envelops of E. tarda. The rGAPDH was administrated into Japanese flounder via IP route for evaluation of the protective ability. Although the specific antibody titer against etGAPDH was increased about 3-fold after 4 weeks post-vaccination, the survival rates of vaccinated Japanese flounder and the control group with wild type E. tarda was were 12.5% and 0%, respectively. Our results indicated that rGAPDH is immunoreactive antigen but that it will not generate protective immunity in Japanese flounder.

• Asian-Australasian Journal of Animal Sciences
• /
• v.24 no.4
• /
• pp.463-470
• /
• 2011

Gonadotropin-releasing hormone receptor (GnRHR) gene is expressed at the anterior pituitary gland and plays a key role in gonad development. This study aimed to investigate molecular genetic characteristics of the GnRHR gene and elucidate the effects of single nucleotide polymorphisms (SNPs) of GnRHR gene on sex steroid level in Japanese flounder (Paralichthys olivaceus). We used polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and sequencing of the GnRHR gene in 75 individuals. We identified three SNPs in the GnRHR gene: P1 locus (C759A and C830T) in the coding region of exon2 which were both linked together and P2 locus (G984T) in the coding region of exon3, which added a new transcript factor (ADR1) and a new methylation site (CG). Only C830T of P1 leads to amino acid changes Thr266Ile. Statistical analysis showed that P1 was significantly associated with $17{\beta}$-estradiol ($E_2$) level (p<0.01) and gonadosomatic index (GSI) (p<0.05). Individuals with genotype BB of P1 had significantly higher serum $E_2$ levels (p<0.01) and GSI (p<0.05) than those of genotype AA or AB. Another SNP, P2, synonymous mutation, was significantly associated with GSI (p<0.05). Individuals with genotype AB of P2 had significantly higher GSI (p<0.05) than that of genotype AA. In addition, there was a significant association between one diplotype based on three SNPs and reproductive traits. The genetic effects for both serum $E_2$ level and GSI of diplotype D4 were super diplotypes (p<0.05). These results suggest that the SNPs in Japanese Flounder GnRHR are associated with $E_2$ level and GSI.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.3
• /
• pp.237-241
• /
• 2002

This study was performed both to explore the host of nervous necrosis virus (NNV) between mariculturing fish species and to examine the phylogenic position of the NNV in Korea. NNV was confirmed on the basis of histopathological and molecular biological examination, then VNN infection was Preyed from either moribund or dead fishes including red drum, Sciaenops ocellatus; oblong rock fish, Sebastes oblongus and flounder, Paralichthys olivaceus. As a result of sequencing for a part of ms, virus from red drum was showed $98\%, $97\%, $86\% and $74\% homology with oblong rock fish, grouper, Japanese flounder and striped jack, respectively. On the other hand, NNV from oblong rock fish was demonstrated $96\%, $85\% and $72\% homology with grouper, Japanese flounder and striped jack, respectively. NNV from red drum and oblong rock fish was exhibited phylogenically distant from the representative NNV, SJNNV originated from striped jack. On the contrary, the viruses appeared to be similar species with Taiwan NNV isolated from culturing grouper.

• Journal of fish pathology
• /
• v.24 no.1
• /
• pp.1-9
• /
• 2011

Viral haemorrhagic septicaemia virus (VHSV) is an epidemic virus in olive flounder Paralichthys olivaceus farms in Korea, since the virus have first isolated in 2001. In the present study, partial glycoprotein (G) gene nucleotide sequences of seven Korean VHSV from cultured olive flounder and wild marine fishes in coastal areas of Korea were analyzed to evaluate their genetic relatedness to worldwide isolates. Phylogenetically, all Korean VHSV formed only one minor cluster including Japanese isolates, in genotype IVa, while the North America isolates formed a different minor cluster in genotype IVa. These results suggest that Korean VHSV could be an indigenous virus in Korean and Japanese coastal areas, but have not been introduced from North America.

• Journal of fish pathology
• /
• v.12 no.1
• /
• pp.56-62
• /
• 1999

Since 1998, mass mortality of the Japanese flounder has widely occurred in the south and west coastal area of Korea. A new serotype birnavirus was isolated during the investigation of the cause of the disease. By the electromicroscopic examination, the isolated virus particles appeared hexagonal and unenveloped with an average diameter 52 to 56 nm. Birnavirus specific fragment was amplified by RT-PCR. High yield of virus (10.3 to 10.8 log $TCID_{50}/ml$) was produced in CHSE-214. RTG-2 and RTE-2 cells. Typical birnavirus CPE was observed in these cells. On the contrary, the virus CPE was not shown in the FHM and EPC cells. By a cross-neutralization test with IPNV Ab, IPNV Sp, IPNV VR-299 and MBV Y6, the isolated virus was closely related to marine birnavirus (MBV).

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.42 no.3
• /
• pp.204-208
• /
• 2009

The withdrawal time of erythromycin in cultured olive flounder was investigated to ensure the food safety of the fish treated with erythromycin. The oral administration of erythromycin was carried out using the experimental diet containing erythromycin (200 mg/kg) daily dose of 40 mg/kg body weight. The 45 day experimental period was broken into 7 days of habituation, 8 days of medication and 30 days of additional feeding without antibiotics. The erythromycin concentration in the flounder muscle had been increased gradually with medication. After 5 days of medication, the concentration increased to its maximum level of 6.05 mg/kg. After discontinuing the antibiotic, the erythromycin concentration decreased drastically and day 9 was below 0.1 mg/kg. The erythromycin concentration had slowly declined from the 6th to the 20th day after medication and disappeared completely after 25 days. From these results, the time needed to reduce the erythromycin level to the 0.2 mg/kg limit adopted by the ED and Japan was suspected to be 4-6 days. Therefore, a reasonable withdrawal time following ED and Japanese regulatory guidelines for erythromycin in the cultured flounder could be estimated to be 10 days.

• Journal of Aquaculture
• /
• v.14 no.1
• /
• pp.57-64
• /
• 2001

In Paralichthys olivaceus and Nibea japonica, response to live air (5hr) or ship (25hr) transportation was assessed, by determining the levels of plasma cortisol, glucose, lactic acid and osmolality, as well as hematological parameters namely hematocrit (Ht), red blood cell (RBC) count, hemoglobin (Hb), corpuscular volume (MCV), corpuscular hemoglobin (MCH) and corpuscular hemoglobin concentration (MCHC). In the experimental series I, the olive flounder was subjected to stress or no stress for 1hr, prior to its air transportation for 5hr. The stress suffered by the flounder prior to air transportation resulted in significant reduction in Ht, but increases in MCH and MCHC. Air transportation led to increases in MCV and MCH in both the stressed and non stressed groups. In the non stressed group it led to significant increase in Ht but decrease in MCHC. In the stressed group, the air transportation led to significant increases in osmolality and plasma cortisol from 5 to 38.5ng/$m\ell$. Non stressed groups did not show significant differences in this before and after transportation. In the experiment II, the red blood cell (RBC) count ranged from 2.5$\times$10$^{6}$ /${mu}ell$ to 2.7$\times$10$^{6}$ /${mu}ell$ in the flounder and 1.9$\times$10$^{6}$ /${mu}ell$ to 2.1$\times$10$^{6}$ /${mu}ell$ in the croaker during the pre- and post-transportation, respectively. In the croaker the shipping led to significant increase in plasma cortisol from 26 to 35ng/$m\ell$ but decrease in glucose from 91.0 to 26.4mg/㎗. For glucose the reverse (39.0 to 51.0mg/㎗) was true for the flounder.

• Korean Journal of Ichthyology
• /
• v.19 no.3
• /
• pp.193-200
• /
• 2007

The samples of cultured flounder (Paralichtys olivaceus) were collected from Tongyeong and Yosu in Korea and Nagasaki in Japan and processed to analyses of body and serum. Body size and weight were not significantly different between Korea and Japan produced. But the body weight of average size of flounder produced from Nagasaki was the highest from the samples. The average of fish body was not significantly different from the samples. The water content of fish body was lower in samples from Nagasaki and fat content was higher in the samples from Nagasaki and followed by Yosu and Tongyeong. The percentage of body water, fat and protein contents was Nagasaki, Yosu and Tongyeong in the order of high values. Japanese flounder showed relatively high content of body fat and muscle. The cholesterol of serum was highest in the samples of Yosu. The triglyceride of serum was highest in the samples of Nagasaki. Lipoprotein was highest in the samples of Nagasaki and enriched fat content in LDL fraction.